This invention relates to a woven tape used for slide fasteners. Particularly, the invention relates to a woven tape having an improved beaded edge to which fastener elements may be firmly and reliably fixed.
Heretofore, a fastener tape has been well known in which a core member is disposed in parallel to one side edge of the tape and warp ends are provided around the outer periphery of the core member, a circular weave being made between the warp ends and the weft picks of the tape body to form a beaded edge comprising the core member and the encircling warp ends. Fastener elements made of metal or injection molded plastics are fixed to the tape by clamping the beaded edge by their upper and lower legs. Since a cord is used as a core member, the cross section of the core member is generally circular. Furthermore, the warp ends are evenly disposed around the core member. Therefore, the resulting beaded edge also has a circular cross section. The tape is first formed in a long continuous woven web and the fastener elements are fixed to the tape by clamping the beaded edge of the tape by their legs. Before the fastener elements are fixed to the tape, the tape is subjected to various processes such as a dyeing process. During these processes, the tape is taken up on a drum or roller and by this taking up operation, the beaded edge constructed as above is pressed into a flat shape. Since the beaded edge has originally a circular cross section, the flattened beaded edge presents generally elliptical configuration. The elliptical shape is disadvantageous because a sharp edge or distinct step is not formed between the beaded portion and the body of the tape. Furthermore, in case of a flat beaded edge it is very likely that the laterally expanded inner side portion of the beaded edge is not received in the space defined by the two legs of an element and the inwardly bent end portions of the legs. If this occurs, securement of the element becomes unreliable and the inwardly bent end portions of the legs damage the weft picks of the beaded edge.
Fastener tapes having the beaded edges of the above-mentioned kind are disclosed in U.S. Pat. Nos. 1,949,889 and 2,061,073 issued on Mar. 6, 1934 and Nov. 17, 1936, respectively and U.K. Pat. No. 758,533 published on Oct. 3, 1956. However, none of them teaches an approach for eliminating the above described shortcomings.